Development and evaluation of nefopam hydrochloride microcapsules

ABSTRACT

An attempt was performed to encapsulate Nefopam hydrochloride, a highly water soluble drug, by a modified emulsion solvent evaporation / extraction technique, using cellulose acetate butyrate [CAB] as a coating polymer. The influence of core/coat ratio [12, 11 and 21 ratio] on the yield, drug loading, size distribution as well as the release characteristics and surface topography of the prepared microcapsules was investigated. The obtained microcapsules exhibited higher encapsulation efficiency and a decreased release rate in simulated gastric fluid [S.G.F. pH 1.2] and simulated intestinal fluid [S.I.F. pH 7.4]. On the other hand, the entrapment efficiencies increased [from 104.66 to 141.26, core coat ratio 11] and the release rate decreased with increasing microcapsule size [from 250 to 512.5 micro m] and/or theoretical drug loading of microcapsules. Kinetic assessment of the release rate of microcapsules using different mathematical models has shown that the release followed Ritger-Peppas diffusion release kinetics